American Journal of Electrical Power and Energy Systems 2017; 6(4): 43-50 http://www.sciencepublishinggroup.com/j/epes doi: 10.11648/j.epes.20170604.12 ISSN: 2326-912X (Print); ISSN: 2326-9200 (Online) Review on S-Shape Characteristics of Pump Turbine for Hydropower Generation Daniel Adu * , Jinfeng Zhang, Yujian Fang National Research Centre of Pumps, Jiangsu University, Zhenjiang, China Email address: adudaniel39@yahoo.com (D. Adu) * Corresponding author To cite this article: Daniel Adu, Jinfeng Zhang, Yujian Fang. Review on S-Shape Characteristics of Pump Turbine for Hydropower Generation. American Journal of Electrical Power and Energy Systems. Vol. 6, No. 4, 2017, pp. 43-50. doi: 10.11648/j.epes.20170604.12 Received: May 23, 2017; Accepted: June 26, 2017; Published: July 26, 2017 Abstract: This paper presents and discussed the results of an experimental investigation of S-shape characteristics of pump turbine. An experimental study of pump turbine has been carried out by many researchers to study its characteristics. By using the experimental results of tested pump of some previous researchers, The Numerical analysis and Experimental studies on the S-shaped characteristics of a pump turbine model, Impact of Parameters on S-shaped characteristics, mechanism of the internal flow of pump turbines as well as measurements of pressure fluctuations on reduced-scale model pump-turbines have been discussed. Keywords: Pump Turbine, Pressure Fluctuations, S-Shaped Characteristics, Parameters 1. Introduction The ability to store electricity is the main problem in electricity production to a large extent based on renewable energy. In reality, as We all know, these sources are sporadic and non-programmable, so it cannot meet the electricity needs of users. One of the most promising and useful means for power storage today is that of the pump storage plants characterized by a good dynamic (fastest way of altering from pump mode to turbine mode) with the provision of good energy. reverse pump turbine (RPT) is the utmost communal mechanical device approved in the new generation of pumped-hydro energy storage it is usually preferred due to their profitability compare to other technical requirements Even though quite a lot of problems in the grid might be answer by Pumped Storage, pump- turbines also desires regular and quicker changes among pumping and generating modes outspreading the operation of the machine at off-design conditions. Nevertheless, pump turbine design comes from the outcome of a cooperation amongst the conflicting targets such as performance of pump and turbine, regulatory capacity, efficiency and cavitation behavior. The design criteria, which are more focused on the behavior of the pumping function, such as the increase in the depth of the flow field at the depth of the flow field can result in the operation of the unstable region (called the S-shaped region) which doesn’t have impact on Francis turbines functioning at the same conditions [1]. In view of the strong fluctuation of the torque caused by the occurrence of instability in the region, the RPT can be affected by a sudden change in the function (from turbine to pump and vice versa), along with substantial fluctuations of the head and flow rate through conceivable self-excited vibrations [2] otherwise water hammers emphasizing not the mechanical equipment alone but the entire power plant [3]. What brought about this S-Shaped characteristic appear to be in relation with the development of vortexes in the pump-turbine partly blocking the flow [4-6]. Established from Some studies indicate that the advancement of stall cells gyrating in the runner channels at 5070% of the rotational frequency of the runner [7-10]. 1.1. Experimental Studies The experimental study of the mechanism of the internal flow of pump turbines comprises of velocity fields measurements and visual observations as well as measurements of pressure fluctuations on reduced-scale model pump-turbines. Owing to the complication of the